EP2830546A1

EP2830546A1 - Variable zone high metal to vessel ratio stent and method

Info

Publication number: EP2830546A1
Application number: EP13708291.3A
Authority: EP
Inventors: Keith Perkins; Samuel Robaina; Jeffery Argentine; Walter Bruszewski; Andrew Kiehl
Original assignee: Medtronic Vascular Inc
Current assignee: Medtronic Vascular Inc
Priority date: 2012-03-27
Filing date: 2013-02-16
Publication date: 2015-02-04
Anticipated expiration: 2033-02-16
Also published as: US9393136B2; US20130261727A1; EP2830546B1; WO2013148011A1

Abstract

A variable zone high metal to vessel ratio stent includes a proximal high metal to vessel ratio zone, a central low metal to vessel ratio zone, and a distal high metal to vessel ratio zone. The proximal high metal to vessel ratio zone is deployed with fixation and sealing to healthy tissue of a main vessel superior to branch vessels and an aneurysm. The central low metal to vessel ratio zone is deployed directly on ostai of the branch vessels. However, as the central low metal to vessel ratio zone is highly permeable, blood flows from the main vessel through the central low metal to vessel ratio zone and into branch vessels.

Description

VARIABLE ZONE HIGH METAL TO VESSEL RATIO

STENT AND M ETHOD

BACKGROUND

Field

[0001] The present application relates to an Intra-vascular device aid method. More particularly, the present appl ication relates to a device for treatment of intra-vascu!ar diseases.

Description of the Related Art

[0002] A convent! onai stent-graft typi call y i nd udes a radi al I y expandabl e re nf orcement structure, formed from a pl urai i ty of annul ar stent ri ngs, and a cyl i ndri cal I y shaped I ayer of graft materi ai , someti mes cal I ed graft d oth, def i ni ng a I umen to whi ch the stent ri ngs are coupl ed. ai n stent-grafts are we! I known for use in tubular shaped human vessels.

[0003] To i Π ustrate, endovascui ar aneurysmal exd usi on i s a method of usi ng a stent-graft to exd ude pressuri zed fi ui d f I ow f om the i nteri or of an aneurysm, thereby reducing the risk of rupture of the aneurysm and the associated invasive surgical intervention.

[0004 ] Stent-grafts with custom side openi gs are someti mes fabricated to accommodate the particular vessel structure of each individual patient. Specifically, as the location of branch vessds emanati g from a main vessel , e.g., having the aneurysm, varies from patient to patient, stent-grafts are fabricated with side openi ngs custom! zed to match the posi ti on of the branch vessd s of the parti oil ar patient. However, custom fabrication of stent-grafts is rd ativdy expansive and time consuming.

[0005] Furt ha, the stent-grafts must be depi oyed such that the custom si de openings are precisely al igned with the respective locations of the branch vessds. This is a rd ativdy complex procedure thus increasing the risk of the procedure.

SUM A Y

[0006] A vari abl e zone hi gh metal to vessd rati o stent i rid udes a proxi mai high metal to vessd ratio zone, a central low metal to vessd ratio zone, and a distal high metal to vessd ratio zone. The proxi mai high metal to vessel ratio zone is deployed with fixation and seal ing to healthy ti sue of a main vessel superior to branch vessd s and an aneurysm. The central low metal to vessd ratio zone is depl oyed di recti y on ostai of the branch vessd s. However, as the central I ow metal to vessel ratio zone is highly permeable, blood flows from the main vessel through the central low metal to vessel ratio zone and into branch vessels. Further, the distal high metal to vessel ratio zone covers and excl udes the aneurysm. As the variable zone high metal to vessel ratio stent is integral , the variable zone high metal to vessel ratio stent is deployed in a single operation which reduces procedure time and complexity.

[ 0007 ] These and other features of embodi ments will be more readi I y apparent from the detailed description set forth below taken in conj unction with the accompanying drawings.

P fcSDis fcr UΕrΓ T S i f~ii t

[0008] FI G.1 is a perspective view of a variable zone high metal to vessel ratio stent in its final configuration in accordance with one embodiment;

[ 0009] FI G. 2 is a cross-sectional view of the vai able zone high metal to vessel ratio stent of FIG. 1 ;

[0010] FI G.3 is a cross-sectional view of a vessel assembly incl uding a del ivery system incl uding the variable zone high metal to vessel ratio stent of FI GS. 1 and 2 in accordance with one embodiment;

[0011] FI G. 4 is a cross-sectional view of the vessel assembly incl udi g the del ivery system at a late?" stage of deploying the variable zone high metal to vessel ratio stent of FIGS. 1 and 2 in accordance with one embodi mait;

[0012] FI G. 5 is a cross-sectional view of the vessel assembly of FIGS.3 and 4 after dep! oyment of the vari abl e zone high metal to vessel rati o stent of FI GS. 1 and 2 in accordance with one embodiment;

[0013] FI G. 6 is a cross-sectional view of the vessel assembly of FIG. 5 il l ustrating tissue ingrowth into the vari able zone high metal to vessel ratio s ent;

[0014] FI G.7 is a cross-sectional view of a vessel assembly incl uding a vari able zone high metal to vessel ratio stent graft in accordance with another embodiment; and

[0015] FI G. 8 is a cross-sectional view of a vessel assembly incl uding a vari able zone high metal to vessel ratio stent graft in accordance with yet another embodiment.

[0016] In the foi l owing description, the same or similar elements are I abd ed wi th the same or si mi I ar reference numbers. DETAI LED DESCRI PTION

[ 0017 ] As an overview and in accordance with one embodiment, referring to FIGS. 1 , 2, and 5 together, a variable zone high metal to vessel ratio stent 100 incl udes a proximal high metal to vessel ratio zone 118, a central low metal to vessel ratio zone 120, and a distal high metal to vessel ratio zone 122. FYoximal high metal to vessel rati o zone 118 is deployed with fixation and seal ing to healthy tissue of a main vessel 304 supeior to branch vessels 308, 310 and an aneurysm 308.

[ 0018 ] Central I ow metal to vessel rati o zone 120 i s depl oyed di recti y on ostai 322, 324 of branch vessels 308, 310, respectively. However, as central low metal to vessel ratio zone 120 is highly permeable, blood flows from main vessel 304 through central low metal to vessel ratio zone 120 and into branch vessels 308, 310 thus perf usi ng branch vessel s 308, 310.

[ 0019] Further, distal high metal to vessel ratio zone 122 covers and exci udes aneurysm 306. As variable zone high metal to vessel ratio stent 100 is integral , i .e., formed of a single piece and not a pl ural ity of separate pieces connected together, variable zone high metal to vessel ratio stent 100 is depl oyed in a singleopa-ation which reduces procedure time and complexity. This is in stark contrast to deploy! ng muiti pi e stents one withi n another to vary the metal to vessel ratio of the resulting muiti stent arrangement.

[ 0020 ] Now in more detail , FIG. 1 is a perspective view of a variable zone high metal to vessel ratio stent 100, e.g., an abdominal aortic stent, in its final configuration in accordance with one embodiment. FI G. 2 is a cross-sectional view of variable zone high metal to vessel ratio stent 100 of FIG. 1. Variable zone high metal to vessel ratio stent 100 is sometimes cal led an endol uminal flow disrupting device.

[ 0021 ] Ref erri ng now to Fl GS. 1 and 2 together, vari abi e zone high metal to vessel rati o stent 100 i ncl udes a proxi mai mai n openi ng 102 at a proxi mal end 10OP of vari able zone high metal to vessel ratio stent 100. Vari able zone high metal to vessel ratio stent 100 further incl udes a distal main opening 104 at a distal and 100D of vari able zone high metal to vessel ratio stent 100.

[ 0022 ] As used herei n, the proxi mal end of a prosthesi s such as vari abl e zone high metal to vessel ratio stent 100 is the and closest to the heart via fhe path of blood flow whereas the distal end is the end furthest away from the heart during deployment. In contrast and of note, the distal end of the del i very system is usuai ly identified to the end that isfarthest from the operator (handle) while the proximal and of the del i very system i s the end nearest the operator (hand! e). [0023] For purposesof clarity of discussion, as used herein, thedis ai end of the del i very system i s the end that i s farthest f om the opa'ator (the end furthest from the handl e) whi I e the di stal end of the prosthesi s i s the end nearest the operator (the end nearest the handle), i .e., thedistai end of the del ivery system and the proxi mal end of the prosthesi s are the ends furthest from the hand! e whi I e the proximal end of the del i very system and thedistai end of the prosthesis are the ends nearest the handl e. However, those of ski Π i n the art wi 11 understand that depending upon the access location, the prosthesi sand del ivery system description may be consistent or opposite in actual usage.

[0024 ] Variablezone high metal to vessel ratio stent 100 is cyl indrical and includes a longitudinal axis L. A main lumen 108 isdefined by variable zone high metal to vessel ratio stent 100 and extends generally parallel to longitudinal axis L and between proximal mai opening 102 and distal mai opening 104 of variable zone high metal to vessel ratio stent 100.

[0025] I accordance with this embodiment, variable zone high metal to vessel ratio stent 100 has a substantially uniform diameter D. However, in other embodiments, variable zone high metal to vessel ratio stent 100 has a non-uniform diameter.

[0026] Variablezone high metal to vessel ratio stent IQO is a semi- permeabl e barri er made of patterned materi a! 108, e.g. , i s a I aser cut si ngl e tube or i s wire formed and welded. Variable zone high metal to vessel ratio stent 100 i nci udes patterned materi ai 108 and a pi ural i ty of hoi es 110 through whi ch f I ui d, e.g., blood, can pass.

[0027 ] Genera! I y , vari abi e zone high metal to vessel rati o stent 100 i s permeable, sometimes called porous, to fluid, i .e., fluid can pass through variable zone high metal to vessel ratio stent 100 and more particularly, through holes 110. This allows fluid, e.g., blood, to pass through variable zone high metal to vessel ratio stent 100 and nourish, e.g., with oxygen and nutrients, the covered vessel wal I . In this manner, hypoxia of the cova'ed vessel wal I is avoided. Further, vari able zone high metal to vessel ratio stent 100 is permeable to tissue ingrowth.

[0028] Longitudinal direction 112 is the direction along vari able zone high metal to vessel ratio stent 100 parallel to longitudinal axis L. Circumferential direction 114 is the direction along the circumference of variablezone high metal to vessel ratio stent 100 in plane perpendicular to longitudinal axis L of variable zone high metal to vessel ratio stent 100. Radial direction 118 is along a radius extending from longitudinal axis L in plane perpendicular to longitudinal axis L of vari able zone high metal to vessel ratio stent 100.

...4... [0029] Generally, there are a plural ty, e.g., three or more, of holes 110 arranged in both longitudinal direction 112 as well as circumferential direction 114.

[0030] Vari abl e zone high metal to vessel rati o stent 100 i nci udes vari abl e metal to vessel ratio zones 118, 120, 122. Vari able metal to vessel ratio zones 118, 120, 122 havedifferent metal to vessel ratios as defined below. Although three vari able metal to vessel ratio zones 118, 120, 122 are illustrated and discussed herein, in light of this disclosure, those of skill in the art will understand that vari able zone high metal to vessel ratio stent 100 includes more or I ess than three vari able metal to vessel ratio zones in other embodiments.

[0031] Vari abl e metal to vessel rati o zones 118, 120, 122 are haei naf ter ref erred to as a proximal , e.g., first, high metal to vessel ratio zone 118, a central , e.g., second, low metal to vessel ratio zone 120, and a distal , e.g., third, high metal to vessel ratio zone 122, respectively.

[0032] Proximal high metal to vessel ratio zone 118 is at proximal end 10OP of vari able zone high metal to vessel ratio stent 100. Distal high metal to vessel ratio zone 122 is at distal end 100D of vari able zone high metal to vessel ratio stent 100. Central low metal to vessel ratio zone 120 is between proximal high metal to vessel ratio zone 118 and distal high metal to vessel ratio zone 122.

[0033] The ratio of material 108 per unit area of proximal high metal to vessel ratio zone 118 1s high, e.g., greater" than or equal 30%. This ratio is sometimes called the metal to vessel ratio (or metal to artery ratio) as it defines the percent of the vessel covered with material 108 per unit area of the vessel . Stated another way, the percentage of proximal high metal to vessel ratio zone 118 formed by material 108 is high, e.g., greater than or equal to 30%, and the percentage of proximal high metal to vessel ratio zone 118 formed of holes 110 is low, e.g., less than or equal to 70%.

[0034 ] Generally, the metal to vessel ratio is defined as the area occupied by material 108 of proximal high metal to vessel ratio zone 118 for a unit area of proximal high metal to vessel ratio zone 118 when in the final configuration. To illustrate, for an X square centi meter (cm²) area of proximal high metal to vessel ratio zone 118, Y percent is formed of material 108 whereas Z percent is formed of holes 110, where Y + Z = 100. Continuing with this example, Y is the metal to vessel ratio expressed as percent.

[0035] To givea specific example for a 40% metal to vessel ratio, for a 1.0 square centi meter area of proxi mal high metal to vessel ratio zone 118, 0.4 square centi meters woul d be covered by materi al 108 whereas 0.6 square centi meters woui d be covered by hoi es 110. The metal to vessel rati o can be expressed as a fraction, ag., 0.4 for this example, or as a percentage, e.g., 40% for this example. To convert, the fraction is multipl ied by 100 to obtain the percentage.

[0036] Although a fixed metal to vessel ratio is set forth, in other embodiments, the metal to vessel ratio of proximal high metal to vessel ratio zone 118 varies in the longitudinal direction 112 and/or in the circumferential direction 114 along variable zone high metal to vessel ratio stent 100.

[0037 ] As set forth above, the metal to vessel rati o i s def i ned when vari abi e zone high metal to vessel ratio stent 100 and thus proximal high metal to vessel ratio zone 118 is in the final configuration. Variablezone high metal to vessel ratio stent 100 is in the final configuration when in its final unconstrained expanded state, sometimes called at nominal deployment. More particularl , when the diameter of variablezone high metal to vessel ratio stent 100 is approximately equal , e.g., 10% to 20% oversized, to thediameter of the vessel in which variable zone high metal to vessel ratio stent 100 is bang deployed and variablezone high metal to vessel ratio stent 100 is at its natural unconstrai ed length at this diameter, vari able zone high metal to vessel ratio stent 100 is in its final state. Generally, once deployed within the vessel at its natural unconstrained length as discussed below, vari able zone high metal to vessel ratio stent 100 is in the final

configuration.

[0038] The final configuration should be contrasted to the constrained configuration of vai able zone high metal to vessel ratio stent 100. Variablezone high metal to vessel ratio stent 100 is in a constrained configuration when variable zone high metal to vessel ratio stent 100 is constrained to a reduced diameter, e.g., within add ivery sheath. Further, variablezone high metal to essd ratio stent 100 is in a constrained configuration when variablezone high metal to vessel ratio stent 100 is constrained to a reduced or expanded length, e.g., by longitudinall compressing or expanding variablezone high metal to vessel ratio stent 100. When in the constrained configuration, either in length, diameter, or both, holes 110 are collapsed resulting in a much higher metal to vessd ratio for vari able zone high metal to vessel ratio stent 100 than when variablezone high metal to vessel ratio stent 100 and is in its final configuration.

[0039] Asdiscussed further bdow, e.g., in reference to FIGS. 3-8, the metal to vessd ratio of proximal high metal to vessel ratio zone 118 is sufficiently high to encourage tissue ingrowth around proximal high metal to vessd ratio zone 118.

[0040] Generally, the metal to vessd ratio of proximal high metal to vessd ratio zone 118 is within the range of 30 percent to 80 percent (30-80%), more suitably within the range of 35 percent to 60 percent (35-60%). In one particular embodiment, the metal to vessel ratio is 40 percent (40%).

[0041] Distal high metal to vessel rati o zone 122 also has a high metal to vessel ratio as defined above. In one embodiment, distal high metal to vessel ratio zone 122 is identical in structure to proximal high metal to vessel ratio zone 118 and thus has the identical high metal to vessel ratio. As discussed further below, e.g., in reference to FIGS. 3-6, the metal to vessel ratio of distal high metal to vessel ratio zone 122 is sufficiently high to encourage tissue ingrowth around distal high metal to vessel ratio zone 122 as wd I as to provide adequate aneurysm exclusion.

[0042] In contrast, central I ow metal to vessel rati o zone 120 has a I ow metal to vessel ratio. Generally, the metal to vessel ratio of central low metal to vessel ratio zone 120 is less than 30%. Asdiscussed further below, e.g., in reference to FIGS. 3-6, the metal to vessel ratio of central low metal to vessel ratio zone 120 is sufficientl low to allow perfusion of branch vessels through central low metal to vessel ratio zone 120.

[0043] !n one embodiment, variable zone high metal to vessel ratio stent 100 isformed of balloon expandable and/or self-expandi g metal , e.g., e.g., formed of Niti no! or stai nl ess steal . I n one embodi ment, vari abl e zone high metal to vessel ratio stent 100 is integral , i .e., a single piece and not a plural ity of separate pieces connected together. For example, a cyl indrical tube of metal , e.g., Nitino! , is iaser cut to form hoi es 110 there! n thus form! ng vari abl e zone high metal to vessel rati o stent 100. The cylindrical tube of metal can be formed from a metal sheet that is bent and welded in one embodi ment. As illustrated in FIG. 2, vari able zone high metal to vessel ratio steit 100 has a thickness!, e.g., equal to the thickness of the cyl indrical tube from which vari able zone high metal to vessel ratio stent 100 is formed.

[0044 ] Variablezone high metal to vessel ratio stent 100 includes a plural ity of serpentine rings 124, 126, 128, sometimes called first, second, aid third serpentine ri gs 124, 126, 128, connected together by connector bars 130.

Serpenti ne ri ngs 124, 126, 128 i ncl ude a zi gzag pattern, someti mes cal I ed a sinusoidal or an alternating repeating pattern. More particularly, each serpentine ring 124, 126, 128 includes a repeating pattern of proximal apexes 132 aid distal apexes 134 connected by struts 136. Proxi mal apexes 132 and di sta! apexes 134 are someti mes cal I ed peaks and val I eys, respective! y, or crowns.

[0045] More particularly, proximal high metal to vessel ratio zone 118 is formed of serpentine ri gs 124 connected together by connector ba"s 130. Central low metal to vessd ratio zone 120 is formed of serpentine rings 128 connected together by connector ba^*s 130. Distal high metal to vessel ratio zone 122 is formed of serpentine ri gs 128 connected together by connector bars 130.

[0046] To provi de central I ow metal to vessd rati o zone 120 wi th a I ower metal to vessd ratio than proximal and distal high metal to vessd ratio zones 118, 122, serpenti ne ri ngs 126 are I arger thai serpent i ne ri ngs 124, 128.

[0047 ] M ore parti cui arl y , each serpenti ne ri ng 124, 126, 128 has a wavd ength and an ampl itude. The wavd ength i s def i ned as the di stance over whi ch the serpenti ne ri ng' s shape repeats i n ci rcumferenti al di recti on 114. The ampl itude is defined as the peak deviation of the serpentine ring from its center position in longitudinal direction 112.

[0048] Serpenti ne ri ngs 124 of proxi mal high metal to vessd rati o zone 118 have a first wavelength λ! and a first ampl itude A1. Serpentine rings 126 of centra] I ow metal to vessd rati o zone 120 have a second wavd ength KZ aid a second ampl itude A2. Serpentine rings 128 of distal high metal to vessd ratio zone 122 have a third wavelength )Q and a third ampl itude A3.

[0049] Wavd ength Λ2 aid ampl i tude A2 of serpenti ne ri rigs 126 of central low metal to vessd ratio zone 120 are larger than wavd ength A1 and amp! itude A 1 of serpenti ne ri ngs 124 of proxi mal high metal to vessd ratio zone 118. I accordance with this embodiment, wavd ength K2 aid ampl i tude A2 of serpentine ri ngs 126 of central I ow metal to vessd rati o zone 120 are al so I arga" than wavdength ^ and ampl itude A3 of serpentine rings 128 of distal high metal to vessd ratio zone 122.

[0050] FIG. 3 is a cross-sectional view of avessd assembly 300 including a dd ivay system 302 including variable zone high metal to vessd ratio stent 100 of FIGS. 1 and 2 in accordance with one embodiment. FIG. 4 is a cross-sectional view of vessd assembly 300 including del ivery system 302 at a lata stage of deploying variable zone high metal to vessd ratio stent 100 of FIGS. 1 and 2 in accordance with one embodi ment.

[0051] Referri g now to FIGS. 3 and 4 together, a mai vessd 304, e.g., the aorta, includes an aneurysm 306. Variable zone high metal to vessd ratio stent 100, someti mes cal I ed a prosthesi s, i s depl oyed i nto mai n vessd 304 to excl ude aneurysm 306 using dd ivery system 302.

[0052] Emanating from main vessd 304 is afirst branch vessd 308 and a second branch vessd 310, someti mes cal led visceral branches of the abdominal aorta The location of branch vessds 308, 310 vary from patient to patient.

Examples of branch vessds 308, 310 ind ude the renal arteries (RA), the superior mesenteric artery (SMA), the bracbiocephal ic artery, the left subclavian artery, the left common carotid, the cel iac trunk, aid the hypogastric artery.

[0053] Del ivery system 302 is advanced to the location of aneurysm 306, e.g., over aguidewire312, for example as illustrated in FIG. 3. Del ivery system 302 includes a tapered tip 314 that is flexible and able to provide trackabi I ity in tight and tortuous vessels. Tapered tip 314 includes a lumen 316 allowing for passageof guidewire312 in accordance with this embodiment. In one

embodiment, del ivery system 302 includes radiopaque mar ker(s) that allow visual ization of del i ery system 302.

[0054 ] To deploy variable zone high metal to vessel ratio stent 100, an i nner member 318 of del ivery system 302 i nd udi ng tapered ti p 314 mounted thereon is held stationary whiiean outer sheath 320 of del ivery system 302 is withdrawn, for example, as illustrated in FIG. 4. Variablezone high metal to vessel ratio stent 100 is radially constrained by outer sheath 320 around inner member 318. I nner member 318 i ncl udes a stent stop or other features to prevent variablezone high metal to vessel ratio stent 100 from moving back as outer sheath 320 is withdrawn.

[0055] Asouta" sheath 320 is withdrawn, variablezone high metal to vessel ratio stent 100 is gradually exposed from proximal end 10OP to distal end 100D of variablezone high metal to vessel ratio stent 100. The exposed portion of variable zone high metal to vessel rati o stent 100 radi al i y expands to be I n conform! ng surf ace contact with mai vessel 304. More particularly, variablezone high metal to vessel rati o stent 100 opposes the wal I s of mai n vessel 304 thus securi ng vari abi e zone high metal to vessel ratio stent 100 in place.

[0056] In one embodiment, variablezone high metal to vessel ratio stent 100 is self -expanding and thus self expands upon being released from outer sheath 320. However, in other embodiments, vari able zone high metal to vessel ratio stent 100 i s expanded with a bal I con or other expansion devi ce.

[0057 ] Although a particular delivery system 302 is illustrated in FIGS. 3, 4 and di scussed above, i n I i ght of thi s di sci osure, those of ski 11 in the art wi 11 understand that any one of a number of del i very systems can be used to dep! oy vari abl e zone high metal to vessel rati o stent 100 and the parti cui ar del i very system used is not essential to this embodiment.

[0058] FIG. 5 is a cross-sectional view of vessel assembly 300 of FIGS. 3 and 4 after deployment of vari able zone high meta! to vessel ratio stent 100 of FIGS. 1 and 2 in accordance with one embodiment. Referring now to FIG. 5, variablezone high metal to vessel ratio stent 100 is in conforming surf ace contact with main vessd 304. Variable zone high metal to vessel ratio stent 100 is deployed such that variable zone high metal to vessel ratio stent 1 0 covers, someti mes call ed j ai I s, ostai (pi ura! of osti um) 322, 324 of branch vessel s 308, 310, respectively.

[0059] More particularly, proximal high metal to vessel ratio zone 118 is deployed with fixation and seal ing to main vessel 304 superior to branch vessels 308, 310 and anajrysm 308, e.g., to healthy tissue of mai vessel 304 proximal to branch vessels 308, 310. This minimizes the risk of migration of variable zone high metal to vessel ratio stent 100. Further, this a! lows fixation and seal ing of variable zone high metal to vessd ratio stent 100 to heal thy tissue even whan aneurysm 306 has a short neck, i .a, when the distance between aneurysm 306 and branch vessd s 308, 310 i s rel ati vel y smal I , as we! I as when aneurysm 306 has a highly angulated neck.

[0060] Central I ow metal to vessd rati o zone 120 i s dep! oyed di recti y on ostai 322, 324 of branch vessels 308, 310, respectively. However, as central low metal to vessel ratio zone 120 is highly pameable, blood flows from main vessel 304 through central low metal to vessd ratio zone 120 and into branch vessd s 308, 310 thus perf usi ng branch vessd s 308, 310. In one embodi merit, branch vessd s 308, 310 are conti nuousl y perfused duri ng the enti re procedure of dep! oy i ng variable zone high metal to vessd ratio stent 100.

[0061] Furtha", deployment of variable zone high metal to vessd ratio stent 100 is rdati dy simple thus minimizing the complexity and thus risk of deploying variable zone high metal to vessel ratio stent 100. More particularly, as the enti re central low metal to vessd ratio zone 120 is permeable, variable zone high metal to vessd ratio stent 100 isdep!oyed without having to rotationaliy position variable zone high metal to vessd ratio stent 100 to be al igned with branch vessd s 308, 310.

[0062] In another embodiment, variable zone high metal to vessd ratio stent 100 includes seal I ops, i .e., cutouts or openings. These seal lops are al igned with ostai 322, 324 of branch vessd s 308, 310. Thus, blood flows from mai vessd 304 through the seal I ops and i nto branch vessd s 308, 310 thus perf usi ng branch vessd s 308, 310 and reducing the risk of occlusion thereof.

[0063] Further, distal high metal to vessd ratio zone 122 covers and exd udes aneurysm 306. M ore parti cul arl y , once vari abi e zone high metal to vessd ratio stent 100 is anchored within main vessd 304, blood flows through mai I umen 106 thus exci udi ng aneurysm 306. [ 0064 ] Further, distal high metal to vessel ratio zone 122 is deployed with fixation aid seal ing to main vessel 304 inferior to aneurysm 306, e.g., to healthy tissue of main vessel 304. This further facil itates excl usion of aneurysm 306 while at the same time minimizes the risk of migration of variable zone high metal to vessel ratio stent 100.

[ 0065] In other examples, variable zone high metal to vessel ratio stent 100 is a bifurcated stent, e.g., variable zone high metal to vessel ratio stent 100 is bifurcated to extend into the Π sac arteries.

[ 0066] As di scussed above, by f ormi ng central I ow metal to vessel rati o zone 120 with a low metal to vessel ratio, branch vessels 308, 310 are adequately perfused through variable zone high metal to vessel ratio stent 100. At the same time, by forming proximal and distal high metal to vessel ratio zones 118, 122 to have a high metal to vessel ratio, tissue ingrowth of main vessel 304 i to variable zone high metal to vessel ratio stent 100 is encouraged.

[ 0067 ] As di scussed above, i n one embodi ment, vari abl e zone high metal to vessel ratio stent 100 is integral , i .e., is a single piece and not a pl ural ity of separate pieces connected together. More particularly, proximal high metal to vessel ratio zone 118, centra! low metal to vessel ratio zone 120, and distal high metal to vessel ratio zone 122 are al l integral parts of vari able zone high metal to vessel ratio stent 100. For example, vari able zone high metal to vessel ratio stent 100 is laser cut from a tube.

[ 0068 ] As vari able zone high metal to vessel ratio stent 100 is integral , vari able zone high metal to vessel ratio stent 100 is deployed in a single operation which reduces procedure time and complexity. This is in stark contrast to depl oy ing mulfi pie stents one within another to vary the metal to vessel ratio of the resulti g muiti stent arrangement.

[ 0069] FI G. 6 is a cross-sectional vi ew of vessel assembl y 300 of Fl G. 5 il l ustrating tissue 602 ingrowth into vari able zone high metal to vessel ratio stent 100. For exampi e, F! G. 6 111 ustrates i ngrowf h of ti ssue 602 after a peri od of ti me, e.g., weeks or months, after the deployment of vari able zone high metal to vessel ratio stent 100 into main vessel 304.

[ 0070 ] Ref erri ng now to F! GS. 5 and 6 together, once depl oyed, ti ssue 602 of main vessel 304 grows through holes 110 of proximal high metal to vessel ratio zone 118 of vari able zone high metal to vessel ratio stent 100. Tissue 602 encases, sometimes cal led encloses or encapsulates, material 108 of proximal high metal to vessel ratio zone 118 of variable zone high metal to vessel ratio stent 100. Accordingly, proximal high metal to vessel ratio zone 118 is sometimes referred to as a proximal fixation region.

[ 0071 ] Thi s i ngrowth of ti ssue 802 provi des secure f i xati on and seal i ng of variable zone high metal to vessel ratio stent 100 to main vessel 304. By providing securefixation and seal ing of variable zone high metal to vessel ratio stent 100 to main vessel 304, the risk of endoleaks into aneurysm 306 and migration of variable zone high metal to vessel ratio stent 100 is minimized.

[ 0072 ] Furtha, as i 11 us rated i n Fl G. 8, ti ssue 802 does not grow over central low metal to vessel rati o zone 120 of variable zone high metal to vessel rati o stent 100. M ore parti cul arl y , bl ood f I ows as i ndi cated by the arrows 604 through holes 110 of central low metal to vessel ratio zone 120 to perfuse branch vessels 308, 310. Accordingly, central low metal to vessel ratio zone 120 is sometimes cal led a perfusion region.

[ 0073] Further, ti ssue 602 of mai n vessel 304 grows through hoi es 110 of distal high metal to essd rati o zone 122 of variable zone high metal to vessel ratio stent 100. Ti ssue 602 encases, someti mes cal I ed end oses or encapasi ates, rnateri al 108 of distal high metal to vessel rati o zone 122 of variable zone high metal to vessel ratio stent 100. Accordingly, distal high metal to vessd ratio zone 122 is someti mes referred to as adistai fixation region.

[ 0074 ] The ingrowth of tissue 602 into distal high metal to vessel ratio zone 122 restri cts expansion of aneurysm 306. I n one embodi ment, aneurysm 306 i s remodeled and essentially el iminated as illustrated in FIG. 8.

[ 0075] In one embodi ment, to encourage ti ssue i ngrowth, vari abi e zone high metal to vessd ratio stent 100 includes a surface treatment, e.g., on proximal and distal high metal to essd ratio zones 118, 122. Illustratively, a thin layer of metal is appl ied, e.g., by sputtering, physical vapor deposit! on (FVD), plasma enhanced chemical vapor deposition (PECVD), or other appl ication technique, to vari able zone high metal to vessd ratio stent 100 to encourage tissue ingrowth.

[ 0076] Examples of suitable metals include gold, stain! ess steel , titanium oxide, and/or copper, or combinations thereof are appl ied to vari able zone high metal to vessd ratio stent 100 to encourage tissue ingrowth.

[ 0077 ] In another embodi merit, the sur ace treatment i ncl udes rougheni ng the surface of van able zone high metal to vessd ratio stent 100 to encourage tissue i ngrowth. For exampl e, the surface i s roughened to have a roughness average (RA) of greater than 1.0 micron (μητι). The surf ace can be roughened by plasma etching, laser etching, sandblasti g, a sdective etch to preferentially etch one component of vari abl e zone h gh metal to vessel rati o stent 100 over" another, or other surface rougheni g technique.

[0078] I n yet another embodi ment, the surf ace treatment i nci udes a growth factor appi ied to vari able zone high metal to vessel ratio stent 100 to enhance tissue i ngrowth i nto vari abi e zone high metal to vessel rati o stent 100. Exampl es of growth factors include vascular endothel ial growth factor (VEGF), platelet-derived growth factor (PDGF), plated-derived epidermal growth factor (PDEGF), fibroblast growth factors (FGFs), basic fibroblast growth factor (bFGF), transforming growth factor-beta (TGF-.beta), piatdet-deri ed angiogenesis growth factor (PDAF) and autologous platelet gel (APG).

[0079] Another example of growth factors include bioactive materials, e.g., a bioactive compound_., drug, therapeutic agent or composition having a biological effect in an animal . Bioactive materials indudesmall molecules, peptides, proteins, hormones, DNA or RNA fragments, genes, cells, genetically-modified eel is, cell growth promoting compositions, inhibitors of matrix metal ioprotei ase, fatty aci ds and autoi ogous pi atd et gel .

[0080] FIG. 7 is a cross-sectional view of a vessel assembly 300A including a vari able zone high metal to vessel ratio stent graft 700 in accordance with another embodiment. Vessel assembly 300A includes main vessel 304, anairysm 306, branch vessels 308, 310, ostai 322, 324 as discussed above in reference to FIGS. 3-8.

[0081] Further, i accordance with this embodi ment, vessel assembly 300A includes first and second bifurcated vessels726, 728, e.g., the iliac arteries. Vessel assembly 300A also include a bifurcated branch vessd 730, e.g., the hypogastric artery, sorneti mes cal I ed f he I nfernal i I i ac artery, branch! ng from f i rst bifurcated vessel 726.

[0082] Vari abl e zone high metal to vessd rati o stent graft 700 i ncl udes a vari able zone high metal to vessel ratio stent 100A, a bifurcated graft material 734, aid stents 736, 738.

[0083] Vari abl e zone high metal to vessd rati o stent 1 QQA i s si mi I ar to vari abl e zone high metal to vessd rati o stent 100 as di scussed above i n reference to FIGS. 1 and 2 and only the significant differences are discussed bdow. Variable zone high metal to vessd ratio stent 100A includes a proximal high metal to vessd ratio zone 118, a central low metal to vessd ratio zone 120, and a distal high metal to vessd ratio zone 122.

[0084 ] !liustrativdy, variable zone high metal to vessd ratio stent 100A is formed of a wire weave. More particularly, proximal high metal to vessd ratio zone 118 is formed of a dense wire weave with fixation and seal ing to main vessd 304 superior to aneurysm 306.

[0085] The wire weave is longitudinally expanded in longitudinal direction 112 over branch vessels 308, 310 to form central low metal to vessd ratio zone 120 of a spare wi re weave. As central I ow metal to vessel rati o zone 120 is highly permeable, blood flows from main vessel 304 through central low metal to vessd ratio zone 120 and i nto branch vessd s 308, 310 thus perfusi g branch vessd s 308, 310.

[0086] Distal high metal to vessd rati o zone 122 is a! so formed of a dense wire weave. Distal high metal to vessd ratio zone 122 is attached, e.g., to the outside, of a proximal region 740 of bifurcated graft material 734. Accordingly, di stal hi gh metal to vessd rati o zone 122 ai I ows for ti ssue i ntegrati on and thus seal mhancement of bifurcated graft material 734 to main vessd 304.

[0087 ] Bifurcated graft maferi ai 734 covers and excl udes aneurysm 306. Further, bifurcated graft material 734 includes first and second legs 742, 744, sometimes called bifurcations, that extend into first and second bifurcated vessd s 726, 728. Optionally, oneor more support structures 746, e.g., sinusoidal stent rings, are attached to bifurcated graft materia! 734 to enhance expansion of bifurcated graft material 734. Although one particular example of bifurcated graft material 734 and support structures 746 is illustrated aid discussed, in l ight of this disclosure, those of skill in the art will understand that other graft designs are used in other embodiments.

[0088] Fi rst and second stents 736, 738 are attached to I egs 742, 744, respectivdy, of bifurcated graft material 734 to enhancedistal fixation of legs 742, 744, to first and second bifurcated vessds 726, 728. In accordance with this embodiment, stents 736, 738 are formed of a wire weave.

[0089] As i 11 ustrated, stent 736 extends over an osti urn 748 of bi furcated branch vessd 730. Blood flows from first bifurcated vessd 726 through stent 736 and into bifurcated branch vessd 730 thus perfusing bifurcated branch vessd 730.

[0090] FIG. 8 is a cross-sectional view of a vessel assembly 3G0B including a variable zone high metal to vessd ratio stent graft 800 in accordance with yet another embodiment. Vessd assembly 300B includes main vessd 304, aneurysm 306, branch vessd s 308, 310, ostai 322, 324, first and second bifurcated vessd s 726, 728, bifurcated branch vessd 730 includi g ostium 748, as discussed above in reference to FIG. 7.

4 - [0091] Variable zone high metal to vessel ratio stent graft 800 includes a variable zone high metal to vessel ratio stent 100B, bifurcated graft material 734, and stents 736B, 738B.

[0092] Variab!ezone high metal to vessel ratio stent 10QB is simiiar to variable zone high metal to vessel ratio stent 100A as discussed above in reference to FIG. 7 and only the significant differences are discussed below. Variablezone high metal to vessel ratio stent 100B i cludes a proximal high metal to vessel ratio zone 118, a central low metal to vessel ratio zone 120, and a distal high metal to vessel ratio zone 122.

[0093] Illustratively, variable zone high metal to vessel ratio stent 100B is formed of a laser cut structure and/or a wire formed and crimped structure.

Proximal high metal to vessel ratio zone 118, e.g., a high metal to vessel ratio mesh, has fixation and seal ing to main vessel 304 superior to branch vessels 308, 310 and aneurysm 308.

[0094 ] Central I ow metal to vessel rati o zone 120 i s formed of I ong longitudinal connectors 844 that extend over branch vessels 308, 310. As central low metal to vessel ratio zone 120 is highly permeable, blood flows from main vessel 304 through central low metal to vessel ratio zone 120 and into branch vessel s 308, 310 thus perf usi ng branch vessel s 308, 310.

[0095] Distal high metal to vessel ratio zone 122 is also a high metal to vessel ratio mesh. Distal high metal to vessel ratio zone 122 is attached, e.g., to the outside, of proximal region 740 of bifurcated graft material 734. Accordingly, di stal hi gh metal to vessel rati o zone 122 ai I ows for ti ssue i ntegrati on and thus seal enhancement of bifurcated graft material 734 to main vessel 304.

[0096] Bifurcated graft material 734, as discussed above in reference to Fl G. 7, covers and excl udes aneurysm 306. Stents 738B, 738B are attached to I egs 742, 744, respectively, of bifurcated graft material 734 to enhance distal fixation of I egs 742, 744 to f i rst and second bifurcated vessel s 728, 728.

[0097 ] In accordance with this embodiment, stents 736B, 738B are formed of a high metal to vessel ratio mesh to promote seal i ng of I egs 742, 744 to f i rst and second bifurcated vessels 726, 728.

[0098] As illustrated, stent 736B is proximal to ostium 748 of bifurcated branch vessel 730. Accordingly, blood flows unrestricted from first bifurcated vessel 726 into bifurcated branch vessel 730 thus perfusing bifurcated branch vessel 730.

[0099] Although treatment of aneurysm 306 s illustrated in thefigures and discussed above, i other embodiments, other vessel defects are treated using devices and methods as described herein. For example, other aortic pathologies such as dissections and penetrating uicers are treated.

[00100] Thisdisd osure provi des exempl ary embodi merits. The scope i s not l imited by these exempl ary embodiments. Numerous variations, whether expl icitly provided for by the specifi cation or implied by the specification or not, such as variations in structure, dimension, type of material and manufacturing process may be i mpi emented by one of ski 11 i n the art i n vi ew of thi s di sd osure.

Claims

WHAT IS CLAIM ED IS:

1. A prosthesi s corripri si ng:

afirst high metal to vessel ratio zone having a high metal to vessel ratio within the range of 30 percent to 80 percent; and

a second low metal to vessel ratio zone having a low metal to vessel ratio I ess than 30 percent, wherei n the f i rst high metal to vessel ratio zone and the second low metal to vessel ratio zone are integral .

2. The prosthesis of Claim 1 wherein the fi rst high metal to vessel ratio zone compri ses f i rst serpent! ne ri ngs and the second I ow metal to vessel rati o zone compri ses second serpenti ne ri ngs, the second serpenti ne ri ngs bei ng I arger than the first serpentine rings.

3. The prosthesi s of CI ai m 2 wherei n the f i rst serpenti ne ri ngs have a f i rst wave! ength and a f i rst ampl itude, and the second serpenti ne ri ngs have a second wavd ength and a second ampl itude, the second wave! ength bei ng greater than the first wavd ength, and the second ampl itude is greater than the first amplitude.

4. The prosthesi s of CI ai m 3 f urther compri si ng:

a third high metal to vessel ratio zone having a high metal to vessel ratio within the range of 30 percent to 80 percent, the third high metal to vessel ratio zone compri si ng thi rd serpenti ne ri ngs, the thi rd serpenti ne ri ngs bei ng smal I er than the second serpenti ne ri ngs.

5. The prosthesi s of CI ai m 4 wherei n the thi rd serpenti ne ri ngs have a thi rd wavd ength and a thi rd ampl i tude, the second wavd ength bei ng greater than the third wavd ength, and the second ampl itude is greater thai the third ampl itude.

6. The prosthesi s of CI ai m 4 further compri si ng connector bars connect! ng the first, second, and third serpentine rings together.

7. The prosthesi s of CI ai m 4 wherei n the f i rst, second, aid thi rd serpenti ne ri ngs compri se proxi mal apexes, di sta! apexes, and struts connecti ng the proxi mal apexes and the distal apexes.

8. The prosthesis of Claim 1 further" comprising:

a third high metal to vessel ratio zone having a high metal to vessel ratio within the range of 30 percent to 80 percent.

9. The prosthesis of Claim 8 wherein the third high metal to vessel ratio zone and the second I ow metal to vessel rati o zone are i ntegral .

10. The prosthesis of Claim 1 whaein the high metal to vessel ratio is within the range of 35 percent to 60 percent.

11. The prosthesis of Claim 1 further comprising:

a asrf ace treatment to encourage ti ssue I ngrowth.

12. The prosthesis of Claim 11 wherein the arf ace treatment comprises a metal .

13. The prosthesi s of CI ai m 11 wherei n the surface treatment compri ses roughening the prosthesis.

14. The prosthesis of Claim 11 where n the surface treatment compri ses a growth factor.

15. A method of forming a prosthesis comprising:

forming afirst high metal to vessel ratio zone having a high metal to vessel ratio within the range of 30 pa-cent to 80 percent; and

forming a second low metal to vessel ratio zone having a low metal to vessel ratio l ss than 30 percent, wherein the first high metal to vessel ratio zone and the second low metal to vessel ratio zone are integral

16. The method of Claim 15 wherein the forming afirst high metal to vessel rati o zone and the forming a second low metal to vessel ratio zone comprises I aser cutti ng a si ngl e tube.

17. A delivery system comprising:

a prosthesis comprising:

af irst high metal to vessel ratio zone having a high metal to vessel ratio within the range of 30 percent to 80 percent; and

a second low metal to vessel ratio zone having a low metal to vessel ratio I ess thai 30 percent, wherein the first high metal to vessel ratio zone and the second low metal to vessel ratio zone are integral ; and

an outer sheath radially constraining the prosthesis.

18. The deli very system of Claim 17 furtha" comprising an i ner member, the prosthesi s be ng radi al I y constrai ned around the i nner member by the outer sheath.

19. A method comprisi g:

depl oyi ng a prosthesi s i nto a mai n vessel compri si ng:

deploying a first high metal to vessel ratio zone of the prosthesis proximal to ai ostium of a branch vessel emanating from the main vessel , the first high metal to vessel ratio zone havi g a high metal to vessel ratio withi the range of 30 percent to 80 percent; and

covering the ostium of the branch vessel with a second low metal to vessel rati o zone of the prosthesi s, wherei n the second I ow metal to vessel rati o zone has a low metal to vessel ratio less than 30 percent, the first high metal to vessel ratio zone and the second I ow metal to vessel rati o zone bei ng i ntegrai .

20. The method of CI ai m 19 f urtha" compri si ng coveri ng an aneurysm of the mai vessel with a third high metal to vessel ratio zone of the prosthesis, the third high metal to vessel ratio zone having a high metal to vessel ratio within the range of 30 percent to 80 percent.

21. The method of CI ai m 19 wherei n the mai n vessel i s the abdomi nai aorta.

22. The method of CI ai m 19 wherei n the dep! oyi ng a prosthesi s compri ses retracti g an outer sheath to expose the prosthesis, wherein the prosthesis self - expands upon being exposed.

23. The method of Claim 19 wherein fluid flows from the main vessel through the second low metal to vessel ratio zone of the prosthesis aid into the branch vessel .

24. The method of CI ai m 23 where n the branch vessel i s conti nuous! y perfused during the deploying a prosthesis.

25. A prosthesis comprising:

a variable zone high metal to vessel ratio stent comprising:

afirst high metal to vessel ratio zone having a high metal to vessel ratio within the range of 30 percent to 80 percent;

a second low metal to vessel ratio zone having a low metal to vessel ratio less than 30 percent; and

a third high metal to vessel ratio zone having a high metal to vessel ratio withi the range of 30 percent to 80 percent; and

a graft material attached to the third high metal to vessel ratio zone.

28. The prosthesis of Claim 25 wherein the variable zone high metal to vessel ratio stent is formed of a wire weave.

27. The prosthesis of Claim 25 wherein the graft material is bifurcated into afirst leg and a second leg.

28. The prosthesis of Claim 27 further comprising:

afirst stent attached to the first leg; and

a second stent attached to the second I eg.

29. The prosthesis of CI ai m 28 wherei n the f i rst stent and the second stent are formed of a wi re weave.

30. The prosthesis of CI ai m 28 where n the f i rst stent and the second stent are formed of a high metal to vessel ratio mesh.